Revolving screen



Nov. 13 3923.

G. M. STEDMAN REVOLVING SCREEN Filed April 27. 1921 Patented Nov. 13, 1923.,

UNE STTES GEORGE M. STEDMAN, OF AURORA, INDIANA, ASSIGNGB TO STEDMANS FOUNDRY &,

'MAGHINE WORKS, OF AURORA, INDIANA, A CGRPOEATION OF INDIANA.

REVOLVING scanner.

Application filed April 27, 1921. Serial no. 464,771.

To all whom it may concern:

Be it known that I, GEORGE 1f. STEDMAN, a citizen of the United States, and residing at Aurora, in the county of Dearborn and State of Indiana, have invented a new and useful Improvement in Revolving Screens, of which the following specification is a full disclosure. i

This invention relates'to tapper mechanism construction and operation, as applied to screening-drums of a type wherein the substance to be screened or sifted is placed, and the drum rotated to accomplish the sifting operationv These drums are usually of hollow, prismatic, regular polygonal configuration and are formed of a series of spider frames centrally mounted upon a shaft and covered with wire screening of the desired mesh. Baffies are generally suitably arranged at the interior to cause the material to be raised and dropped upon the lowermost faces of the drum. This invention does not pertain to the drum structure but only-to the means for vibrating the drum walls. The adherence of the substance being screened within the interstices of the screen material at the interior of the drum prevents the proper functioning of the screen, and much difliculty has been experienced 1n loosening the adhered substances therefrom, throughout the entire area of the screen walls.

An object, therefore, of this invention is to percussively vibrate the drum walls to loosen the adhered substance, this object being furthered by successively sharplytapping or striking and vibrating each wall, throughoutits entire area, while the .wall is in its uppermost position, or by striking the periphery of the drum at a determined point or points, and with predetermined frequency at each cycle of revolution.

Another object is to provide for delivering whip-like blows to the walls, through the medium of strips or bars fastened to said walls, these blows being delivered in such a manner that the drum walls are permitted to vibrate freely thereafter.

Another object is to provide for varying the intensity of the whip-like blows.

Other objects and certain advantages will appear in the description of the drawings, forming a part of this specification, and reference is made to said drawings, in which:

Fig.1 is a side elevation of one form of screening machine, portions of the side wall of the same being broken away to show my improved tapper construction in operable conjunction therewith.

Fig. 2 is an end View of Fig. 1.

Fig. 3 is an enlarged fragmentary View of the structure of Fig. 2, showing in full and in dot-and-dash lines the tapper action.

The numeral 1 generally designates atype of machine technically known as a screen, comprising a suitably enclosed frame structure, within which, and mounted lengthwise thereof for rotation, is a drum 2 of any preferred hollow prismatic or cylindrical formation, in this instance, having a cross sectional configuration of a regular hexagon, which may be composed of spider-frames .over which screen material 3, of suitable mesh, is stretched, the drum structure per se forming no part of my invention.

7 and 8, and is rotatable through any suitable means indicated at 9. The substance to be screened is introduced at the upper interior of the inclined drum through a hopper '10,'a portion of the same passing through the screen, the residue being discharged at the lower end thereof.

Dpon'each outer face of the taut screen material centrally thereof and spaced longitudinally thereon are a plurality of wooden or metallicstrips or bars 11, each function ing to sustain whip-like blows imparted thereto by a corresponding tapper-arm 12. These arms are rigidly but adjustably mounted upon a shaft 13, held in suitable bearings let and 15 at one side of and slightly above the drum 2, and the shaft and arms i thereon are operated simultaneously to give springing whip-like or percussion blows to the bars 11, when any one of the drum faces is in its uppermost position, the rotation of the drum bringing each row of rods or bars 11 consecutively into a position to receive the said blows. The tapper arm shaft 13, at one end, and outside of the screen enclosure,

is provided with a trip arm 20 rigidly but adjustably mounted thereon, its outer end 21 being engageable with the stepped teeth 22, of a trip wheel 23, rigidly mounted upon the shaft. 4, the teeth of said wheel corresponding and being equal in number to the drum faces, or of such a number as will act inner 1 surface and within the interstices" thereof. I

I downward movement are sprung or flexed to give the whip-like blow to the bars and e In order to adjust the throw of the tapper. arms and to increase or decrease theforce and vary the quality of their whip-like blows conformable to requirements, adjustment and bumper means are providedg of which adescription follows:

Attached to the tri arm 2O is a bumper 30, in the form of a ru ber disk, which bumper is designed to contact a headed screw 31, held in a screw threaded boss 32 and adjustable therein,-the boss forming an integral part of a supporting iron 33 attached to the'sid'e of the screen frame. A set nut 34: is provided for holding the screw 31 in its adjusted position. The screw adjustment is made, (see Fig. 2), so that the outer end of thetrip arm, in its lower position, does not engage the trip wheel 23, and in this position, the outer ends12 of the tapper-arms are spaced slightly above the bars 11. It has been found that the positioning of the ends of the two arms'lQ and 20 in relation respectively to the bars and to the trip wheel, prevents a'backward snap' of-the arms after the bars have received theirblows, and after the drum wall isthus allowed to vibrate freely. Inasmuch as'the ends of the tapper arm are normally spaced from the bars 11, the armsin their arrested screen wall. 7

To increase or decrease the percussion blow of the hammer arm 12, it is provided with a weight 36 adjustable upon the arm' toward and from the'free end thereof, which will also vary the vibratory motions of the arm against'the screen bars 11 necessary for an efiicient cleansing of the screen.

The above described features are important and have been found to increase the output of the screen fifty per cent.

1. In a device of the class describechthe combination with a rotatable foraminous walled polyfaced' drum, of bars upon each' face of said drum, intermediate thereof, arms momentarily contactable with I said bars, and means for causing said arms to momentarily contactsaid bars when any face of the said drum is in its uppermost position.

"face of said drum,

spaced relation longitudinally and circum- Having described my invention, I cla1m:-'

arms contactable with said bars for giving whip-like blows thereto, and means for automatically operating said arms to cause successive vibration of each of said walls. when in-'their* -nppermost position.

3. In a tapper mechanism, the combinaation with a rotatable foraminous walled polyfaced drum, of bars upon each outer intermediate thereof, arms contactable with said bars, for vibrating the same and said walls, when in their "uppermost position, and means automatically controlling the beating motion of said arms. 1 In" a tapper mechanism, a rotatable foraminous walled polyfaced drum, intermediate thereof, bars upon each face of said 'drum,arms contactable with said bars, andtrip means for actuating said arms for delivering whip-like blows to said bars.

- 5. In a tapper mechanism, the combination with a rotatableforaminous walled polyfaceddrum, of-bars upon each face of saiddrum, intermediatethereof, means for delivering wh p-like blows to each Of'SEtlCl was '11 its uppermost position, said means comprising a rotatable shaft, arms attached to said shaft, and overhanging said bars, and a trip arm attached to said shaft e'ngageable with a ratchet wheel, rotatable with said drum, and adjustable bumper means engageable with said trip arm for spacing "said arms from said bars.

In a tapper mechanism the combination with a rotatable polyfaced foraminous walled drum, "of bars upon each face of said drum, intermediate thereof, meansfor delivering whip-like blowsto each of said Walls in its uppermost position, said means comprising arms attached tc a rotatable shaft, and overhanging said bars, a triparm also attached to said shaft and engage able with a stepped wheel rotatable with said drum, and bumper means coo erating with said trip arm, for adjusting t e same relative to said stepped wheel.

7. In a device of the class described, a rotatable screen wire drum a plurality of bars secured to the periphery ofthe drum longitudinally with the aXis thereof in engageable with a stepped wheel rotatable with said drum, and bumper means cooperating withsaidtrip arm, for adjusting the same relative to said stepped wheel. 7

iting the striking stroke thereof, and means on said hammer for varying its pressure force.

In witness whereof, I hereunto subscribe 16 my name, as attested by the two subscribing Witnesses.

GEORGE M. STEDMAN. Witnesses:

L. A. BE'CK, J. C. JUNIUS. 

